You're blowing that way out of proportion. All that was said was that it wasn't going to be easy to get all 15+ girls. Not impossible.
It's just that at this stage I'm already tired of notifications from three, what will happen from 6 or 15 I don't even want to think about...

And it's hard for me to ignore "notifications" Especially since there may be something important there and not just "good morning"
You forgot to answer about relationships

I'll duplicate it here.
As I understand it, some girls in couple or trio relationships will have some special interactions?
Will it be shown somehow obviously in the game? That they are girlfriends or rivals or something else, and there will be some special relationships/scenes with them if you date them?
And another question, will it be possible to end relationships? For example, if there is someone extra in the relationship who prevents you from seeing these special interactions, so as not to go through the whole game again, or simply for people who want to date other girls but not be in a
harem poly with a bunch of other girls.
It is clear with some consequences, so that they do not abuse and constantly dump everyone in a row, let's say the girl will be angry/crying depending on her character, and then for some time she will not talk to you, and then for some time she will not want to listen to you (go with you or leave from somewhere) And only then after some time again agree to date you, you can also reduce the love and trust points by half, and so that you can breakup no more than once, after which she will no longer agree to a relationship (realistic?) of course, insert something like this before the 2nd breakup: